Clean, wash and cut the leek into fine strips. Cut tomatoes crosswise, briefly boil water over them, peel, quarter, seed and cut into cubes. Drain beans and tuna.
Peel and finely dice the onion and garlic. Mix vinegar, lemon juice, salt and pepper. Whip the oil into it. Mix the salad ingredients with the marinade. Wash parsley, dab dry, cut into strips and stir in.
Arrange in a bowl.